What does the below commands do on a router

hardware counter feature subinterface out

hardware counter feature subinterface in

hardware counter feature subinterface in layer2

hardware access-list mechanism tcam

In an Arista device, the configuration commands you've shown are related to hardware counters and access control mechanisms, particularly dealing with subinterfaces and TCAM (Ternary Content Addressable Memory). Let’s break down each command and its Cisco equivalent:

1. Hardware Counter Feature Subinterface Out / In

Arista: These commands enable hardware-level counters for traffic coming in and out of subinterfaces. Subinterfaces are logical divisions of physical interfaces used to segment traffic, often in VLANs or different routing contexts.

Layer 2 refers to the data link layer of the OSI model, where switches operate.

These counters help track packet and byte counts at the hardware level, offering precise traffic statistics without impacting performance

Cisco Equivalent:

In Cisco, similar functionality is achieved with show interfaces and show counters, which display packet statistics on physical interfaces and subinterfaces.

Cisco commands like show interfaces [subinterface] counters will show per-interface packet counters.

Cisco routers use hardware-based counters inherently for performance reasons, but specific configuration for tracking subinterface counters may not be needed.

Hardware Access-list Mechanism TCAM

Arista: This command configures the Access Control List (ACL) processing to occur in TCAM memory. TCAM allows for high-speed lookups of ACLs and routing decisions. It’s particularly useful when processing large numbers of ACLs or routing entries.

TCAM enables fast matching of multiple fields (e.g., IP address, port, protocol) in one clock cycle, which is ideal for high-throughput devices.

Cisco Equivalent:

Cisco devices, especially in the Catalyst and Nexus series, also use TCAM for fast ACL processing and route lookups.

The equivalent Cisco configuration is typically built-in, but it can be checked or tuned using commands like:

show platform tcam utilization

or by configuring specific ACLs to be processed in hardware. For instance, you might use:

ip access-list hardware use tcam

references:

OpenAI